Selenium enhances antioxidant activity and photosynthesis in Ulva fasciata

Enrichment of selenium (Se) by seaweed is of great significance for mariculture. In this study, the green alga Ulva fasciata was cultured with a selenite (Na2SeO3) concentration from 0 to 1,250 mg L-1. Se accumulation in the algal biomass was linearly related to Na2SeO3 concentration in the culture medium. Lower Se concentrations (a parts per thousand currency sign750 mg L-1) increased the activities of guaiacol peroxidase (GPX), catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) and the content of photosynthetic pigments, and as well induced lipid peroxidation (LPO) and intracellular reactive oxygen species (ROS) levels. Meanwhile, the cell growth rate and concentrations of organic Se increased. In contrast, these changes were the opposite in U. fasciata exposed to Se concentrations higher than 750 mg L-1. In all cases, Se-Ulva was able to remove inorganic nutrients effectively. Therefore, U. fasciata is tolerant to Se, and Se-Ulva has potential as a source of antioxidative food and an effective control of eutrophication.